Sticking with I field is made for fail. Go normal mode, spam flashlight, rush close, shoot the V beam, switch to I-Field and backpedal while alternately shooting BMG/VSBRs. Melee only to counter, abuse V beam and mode 1 flashlight.
V2A is better than most people think...if only they stopped using the BMG as their sole weapon!
Go attack/HP-Attack/HP-DEF. They all work, depending on your playstyle, but if you are a rusher, go full attack or HP-DEF.